An air cycle environmental control system (ECS) may be used to regulate the conditions of an enclosed environment such as an aircraft cabin. An air cycle ECS generally includes; a compressor for pressurizing air input thereto, and a turbine for driving the compressor and for expanding and cooling the air. The ECS may be powered by the air input thereto from a compressor section of an engine or from an auxiliary power unit (APU).
It is known to integrate an air filtration system or an air filter within an air cycle ECS to protect the inhabitants of the enclosed environment. Some filters and filtration systems, however have a limited life. A limited life may not be desirable when the inhabitants must be protected for longer periods of time.